Here's how NASA watched North Alabama's snow from space (photos)

HUNTSVILLE, Alabama - Watching the weather from space is a daily job for scientists at NASA's Short-term Prediction Research and Transition Center (SPoRT) here. But getting a chance to try out their satellite tools on snowfall in Alabama is something special. It happened this week, and the results show not only the snowfall from space, but a window inside research that will change future weather forecasting in America.

These images were taken by NASA's MODIS imager aboard the TERRA satellite orbiting the Earth. MODIS sees different wavelengths of light, some visible to the eye and some not visible, explains Huntsville scientist Kevin Fuell, and those wavelengths give valuable views of events like snow.

Typical true color images like the one of North Alabama snowfall in this gallery are a combination of red, green and blue wavelengths. But the red wavelength is particularly sensitive to snow and ice, creating the clear images here of snow cover. The green color represents bare ground. In the parts of the images where the snowfall seems lighter, the likely reason is different tree canopies that kept it from all reaching the ground.

Why use different filters if you're just watching the weather for forecasting purposes? For one thing, snow and clouds are both white in true-color images. Using what we used to call the "false color" images of red and green, Fuell said forecasters can easily tell the difference between cloud cover and snow cover.

These false color images have other value. Over time, a series of images will let forecasters, emergency responders and land use managers better monitor the change in snow cover and understand its rate of melting. They can help anticipate flooding and lessen the need for dangerous field surveys.

Fuell says the work being done by SPoRT in Huntsville will find its way onto the next generation of NASA satellites. "It's the wave of the future" for forecasting, he said.

SPoRT is based at the National Space Science and Technology Center on the campus of the University of Alabama in Huntsville and is a partnership between NASA and UAH.